Mathematical Models and Solution Methods for Vehicle Routing Problems

In this study, classical vehicle routing problem, open vehicle routing problem and split delivery vehicle routing problem are examined and for the regarding problems, new mixed integer single objective and multi-objective mathematical models are developed. In the context of this thesis, heterogeneous fleet vehicles are considered. While in single objective models total routing cost (cost per kilometer) and fixed costs for leaving depot minimization is aimed, in the multi objective mathematical models, because of the availability of different types of vehicles in the heterogenous fleet vehicle routing problems, vehicle type minimization is also aimed which is not considered in literature previously. Weighted sum scalarization method is applied for the multi–objective mathematical models. New models, for the small size of problems are solved in GAMS package software, for the large sized problems, tabu search algorithm is applied. This algorithm is applied to the test problems in the literature and computational results are presented with comparison.